New Smart 12v 5w Portable Car Boat Power Solar Panel Battery Backup Charger Car battery maintainer can charge 12V batteries with the power of the sun and create 5 watts of energy Mono-crystalline silicon panel works in all daylight conditions and is weatherproof (some rain drop is OK, but not completely rainproof, for added durability Works with automobile, motorcycle, tractor, boat batteries and more No-load voltage: 18-23VDC; Load voltage: 18V Output current: 250-280mA(0.2A-0.28A)